POTENTIAL OF TETRAPLOID RED-CLOVER AND ITS ROLE IN UNITED-KINGDOM

A major advantage of tetraploid clover is its ability to provide high yields of protein-rich herbage for 2-3 yr without the use of fertilizer N. It is widely adapted geographically and to a range of soil types. Tetraploid red clover also has notable resistance to clover rot disease, which contributes to its persistence when the disease is present. As a forage for livestock, it has high acceptability, voluntary intake and efficiency of conversion characteristics. Tetraploid red clover has an inherently low seed setting ability so expansion in the acreage grown could be limited by seed supply. In its utilization by livestock, bloat is a possible hazard when grazed but is much less likely when conserved. Morphologically, it is better suited to cutting than to grazing and the main role indicated is conservation, particularly for silage. In common with diploid red clover, tetraploid clover contains the estrogen, formononetin. Initial success had been reported in reselection of existing material for low-formononetin content. The silage role of the tetraploid red clover crop is more clearly seen in arable farming systems where it makes an ideal break crop. In grassland systems, its role is in the conservation block, but it fits in less well to a long-rotation grassland system since the crop requires renewal after 2-3 yr.